Kids: Can birds use both of their eyes at the same time?
Photo: Flickr user Marko_K
It seems like a crow can use only one eye at a time …
Crows are like most birds in that their eyes are on either side of the head, not in front as human eyes are.
This gives birds a wider visual field of view than humans – and the ability to see in opposite directions at the same time. A crow can use both eyes at once. But its binocular vision – the range in which it can focus both eyes on a single image – is very limited.
And that’s basically true for most birds.
In humans, 120 degrees of our 180-degree visual field is binocular. In other words, for most of our field of view, we use both eyes at once. A pigeon has a visual field of 340 degrees – almost all the way around its head. But both eyes overlap in only 20 degrees.
That’s why the vision of most birds is considered mostly two-dimensional, in contrast to the three-dimensional vision of mammals. When a bird looks at an object in the range where binocularity fails, it may compensate by turning and tilting its head, to look first from one angle, then from another. As always, there are exceptions. Owls, whose eyes point forward, have good binocular vision – especially helpful in judging distance and depth.
